Add instructions for Claude

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+This is a Rust monorepo. The primary active project is **Visions**, a tabletop RPG game management application with WebSocket-based real-time communication. It uses:
+- **Server**: Axum web framework with SQLite (rusqlite)
+- **UI**: Yew (WebAssembly) with yew-router
+- **Shared types**: visions-types crate shared between server and UI
+- **Component library**: glimmer-yew provides reusable Yew components
+
+## Build Commands
+
+```bash
+# Build server
+cargo build -p visions-server
+
+# Build UI (requires trunk)
+cd visions/ui && trunk build
+
+# Run server (requires env vars)
+DATABASE_PATH=... RELYING_PARTY=... RELYING_PARTY_ORIGIN=... PWA_BASE_URL=... cargo run -p visions-server
+
+# Run all tests
+cargo test
+
+# Run specific test
+cargo test -p visions-core test_name
+
+# Run integration tests for server
+cargo test -p visions-server --test integrations
+```
+
+## Architecture
+
+### Visions Crates
+- **visions/core**: Business logic, database layer, App struct. Uses nested `Result<Result<T, Error>, Fatal>` pattern for error handling.
+- **visions/server**: Axum HTTP/WebSocket handlers and routing. Handlers use `http_adapter` to convert nested results to HTTP responses.
+- **visions/types**: Shared types between server and UI. Uses `identifier!` macro to generate ID types (UserId, GameId, etc.).
+- **visions/ui**: Yew WebAssembly frontend. Uses `StateProvider` for app state, `StyleProvider` for theming.
+
+### glimmer-yew
+Reusable Yew component library with styling via `stylist`. Components use `Stylesheet` context for theming. Key exports in `prelude` module.
+
+## Rust Style Guidelines
+
+### Error Handling
+Use nested results to separate recoverable errors from fatal errors:
+```rust
+fn fallible() -> Result<Result<(), Error>, Fatal>
+fn search() -> Result<Option<()>, Fatal>
+```
+Fatal errors should never be caught except at the top level. Recoverable errors should never be promoted to fatal.
+
+### Let/Else Bindings
+Prefer let/else over match for unwrapping:
+```rust
+// Preferred
+let Some(game) = db.game(&image.game)? else {
+    return Ok(Err(Error::NotFound(image.game.as_str().to_string())));
+};
+
+// Avoid
+let game = match db.game(&image.game)? {
+    Some(game) => game,
+    None => return Ok(Err(Error::NotFound(image.game.as_str().to_string()))),
+};
+```
+
+### Test Style
+Tests use SCENARIO/GIVEN/WHEN/THEN comments and `cool_asserts::assert_matches!`:
+```rust
+/// SCENARIO: Description
+/// GIVEN: Preconditions
+/// WHEN: Action
+/// THEN: Expected outcome
+#[tokio::test]
+async fn test_name() {
+    // GIVEN: ...
+    let support = TestSupport::new().await;
+
+    // WHEN: ...
+    let result = support.app.some_action().await;
+
+    // THEN: ...
+    assert_matches!(result, Ok(Ok(value)) => {
+        assert_eq!(value.field, expected);
+    });
+}
+```
+
+## Yew Component Guidelines (glimmer-yew)
+
+### Naming
+- Name components naturally (e.g., `Button`, not `ButtonComponent`)
+- Properties struct: `<ComponentName>Props`
+
+### Properties
+- Use `AttrValue` for string properties
+- Use `Prop<T>` wrapper for sizable non-string properties
+- Always accept `#[prop_or_default] pub class: Classes`
+- Callbacks: `on_<action>` with `#[prop_or(Callback::from(|_| {}))]`
+- Optional properties: `#[prop_or_default]`
+
+### Cloning in Callbacks
+Use the `clone!` macro from glimmer-yew:
+```rust
+use glimmer_yew::clone;
+
+let on_click = Callback::from(clone!(state, move |_| {
+    state.set(new_value);
+}));
+
+// Multiple values
+clone!((state, props), move |_| { ... })
+```
+
+### Styling
+- Components should have no margin
+- Avoid CSS nesting except for pseudo-selectors
+- Use `stylist::css!` macro with stylesheet tokens from context